1. Field of the Invention
The present invention relates to a method of location registration to base station side conducted by mobile machines in a mobile communication network, and more particularly to a mobile communication network using a moving network, in which, when users carrying mobile machines move on a train or the like, location registration is conducted by using particular location information assigned to a particular area in advance without using conventional location information.
2. Description of the Related Art
In a mobile communication system, when transmission is conducted to a particular mobile machine existing in a service area, an operation is conducted in which an area including the location of the mobile machine in the service area is specified to some extent and only base stations in the specified area make a call for the mobile machine.
For the above reason, mobile machines have to register the locations thereof to a network side such as a core network side in advance. And this operation is called location registration, and an area serving as a unit of the location registration is called a location registration area.
Each mobile machine has to conduct location registration to such a network side as a core network side as it enters in another location registration area as it moves. In order to conduct such location registration, each mobile machine stores location registration area information of the current location thereof, monitors the change of the location registration area information as the mobile machine enters in another radio zone and transmits new a location registration signal to a core network side when the change of the information is detected. The word “radio zone” used here means an area which a radio signal from one base station can cover. And one location registration area consists of a plurality of radio zones generally.
The following publications disclose techniques of location registration, method of setting location registration areas, method of switching to a train travel mode, and a mobile phone system in a toll road, in mobile communication systems.
In Japanese unexamined patent application publication No. 11-7562, a mobile phone system in a toll road is disclosed in which a cost of equipments can be reduced by employing a configuration in which installations of special devices dedicated for the collection of the tolls is made unnecessary just by installing wireless base stations at the entrances and the exits of the toll roads utilizing the existing mobile phone system.
In Japanese unexamined patent application publication No. 11-355835, a method of location registration is disclosed in which, when mobile machines exist in a traveling space such as a bus or a train, and move together with the traveling space, location registration operations of a plural mobile machines (for example, n mobile machines) in the traveling space are represented by the location registration of the traveling space by updating registered locations of the mobile machines depending on the update of location registration of the traveling space so that the frequency of the location registration can be reduced to 1/n.
In Japanese unexamined patent application publication No. 2000-23234, a technique is disclosed in which the frequency of the location registration by each mobile communication terminal is reduced by setting areas with high percentage that the mobile communication terminals are in the area for respective mobile communication terminals as logical location registration areas so that load of location registration processings in a mobile communication system can be reduced.
In Japanese unexamined patent application publication No. 2000-152314, a technique is disclosed in which, when there is a difference between location information Pb reported from a base station in a microcell system and location information Pa reported from a base station for a mobile phone service, the location information Pb is transmitted to a switching machine of a mobile phone so that location of mobile terminals in a radio zone corresponding to a base station in a microcell system can be detected.
In Japanese unexamined patent application publication No. 2001-169332, a technique is disclosed in which dynamic traffic information of mobile machines is collected and when the frequency of location registration request exceeds a predetermined value, an area to be registered as a destination is incorporated in a registered current area so that new location registration request is prevented from occurring.
In Japanese unexamined patent application publication No. 2002-165255, a technique is disclosed in which a plurality of division patterns for dividing a communication service area into a plurality of location areas and mobile machines select division patterns according to their mobile characteristics in order to conduct location registration so that loss of traffic concerning the location registration and receiving can be avoided.
In Japanese unexamined patent application publication No. 2002-300632, a technique is disclosed in which it is certainly determined that users carrying mobile machines are on a train, and the mobile machines are turned off or the modes thereof are switched into a manner mode or train travel mode or the like, based on the determination.
However, in the above techniques there is a problem that when users carrying mobile machines move for a long distance on a public conveyances such as a train, a bus or an airplane, location registration of a large number of mobile machines carried by the users on the conveyances simultaneously occurs inevitably every time as the mobile machines enter in another location registration area. This problem occurs similarly when users carrying mobile machines move on a speedway on automobiles. Although, many location registration areas are provided respectively corresponding to traveling routes and speedways for trains and automobiles, the location registration areas can be defined as sets in advance.
As described above, when users carrying mobile machines move on a train for example, there are three problems. The first problem is that there is an increased load on a network by location registration accompanied with movement of mobile machines. The second problem is that the power consumption of mobile machine side and network side is increased by the location registration. The third problem is that quality of wireless transmission path for other mobile machines is deteriorated due to the location registration. These problems are further explained, referring to FIGS. 1 to 3.
In 3GPP (Third Generation Partnership Project) as an organization for establishing specifications of the third generation mobile communication system, an expanded version of W-CDMA (Wideband Code Division Multiple Access) system for wireless access system and an expanded version of GSM (Global System for Mobile Communication) for core network system are employed. And in this 3GPP specification, wireless communication service area is defined by location areas LA for a plurality of circuit switches (CS) or routing areas RA for packet switch (PS) and location information is managed by core network side. For example, when transmitting to a mobile machine, a paging request is issued to a radio network controller (RNC) existing among a core network and base stations by using the managed location information in the core network. The RNC conducts paging for the area to be reported about the request of receiving, corresponding to the paging request.
FIG. 1 explains a relationship between location areas LA and routing areas RA in a 3GPP system. In FIG. 1, one LA contains one or more RAs generally. Each of one or more LAs is managed by a mobile switching center (MSC). Also, each of one or more RAs is managed by a subscriber node SGSN (serving GPRS support node).
FIG. 2 explains location registration processings along the traveling route of a train or the like. When many users carrying mobile machines move on a train in a mobile communication network, many mobile machines conduct location registration for changing location information LA/RA at once. Accordingly, there occurs an instantaneous increase of load due to these location registrations in the mobile communication network and the core network.
FIG. 3 explains quality deterioration of wireless transmission path due to an increase of a frequency of location registration. In FIG. 3, it is shown that increase of both of frequency of location registration and power consumption simultaneously occurs, corresponding to the travel of a train or the like at a time, that is, a time when the train passes the location registration occurring point. In other words, accompanied with a rapid increase of location registration, quality deterioration of wireless transmission path occurs and power consumption of both of network side and mobile machine side is increased due to the required location registration. Especially, the mobile machines which are battery-operated have to reduce the frequency of the location registration as much as possible in order to suppress the power consumption.
However, the above techniques cannot prevent the increase of the frequency of location registration when a large number of users carrying mobile machines move on a train or the like. Even in the technique of Japanese unexamined patent application publication No. 11-355835, location registration processings accompanied with the travel of a train are necessary and there is a problem that all of the location information of respective mobile machines have to be updated corresponding to such location registration processings.